/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hive.ql.exec.tez;

import java.io.IOException;

/**
 * Key-values interface for the Reader used by ReduceRecordSource
 */
public interface KeyValuesAdapter {
  /**
   * Get the key for current record
   * @return
   * @throws IOException
   */
  Object getCurrentKey() throws IOException;

  /**
   * Get the values for the current record
   * @return
   * @throws IOException
   */
  Iterable<Object> getCurrentValues() throws IOException;

  /**
   * Move to the next record
   * @return true if successful, false if there are no more records to process
   * @throws IOException
   */
  boolean next() throws IOException;
}